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Alien vs Immigrant Difference and Comparison Diffen.
An alien is someone who is a citizen of a foreign country. An alien is subject to host country laws regarding non-citizens travel, employment, education, and residence. These laws require registration and documentation defining their status while they are in the host country.

Alien law Britannica.com.
See Article History. Alien, in national and international law, a foreign-born resident who is not a citizen by virtue of parentage or naturalization and who is still a citizen or subject of another country. In early times, the tendency was to look upon the alien as an enemy and to treat him as a criminal or outlaw.

Alien definition and meaning Collins English Dictionary.
Such an attitude is alien to most businessmen. An alien is someone who is not a legal citizen of the country in which they live. Both women had hired illegal aliens for child care. When war broke out, he was interned as an enemy alien.

The Rights of Non-Citizens.
Significance According to Article 24 of the International Covenant on the Civil and Political Rights, every child has the right to acquire a nationality. Refugee A person who owing to a well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his or her nationality, and is unable to or, owing to such fear, is unwilling to avail himself or herself of the protection of that country or return there because there is fear of persecution. United Nations Convention Relating to the Status of Refugees 1951 and Protocol 1967. Significance Under the international human rights principle of non-refoulement, a state cannot deport an alien in any manner to a border of a territory where his or her life or freedom would be threatened on account of his or her race, religion, nationality, membership in particular social group, or political opinion.

Alien legal definition of alien.
An alien has a right to acquire personal estate, make and enforce contracts in relation to the same he is protected from injuries, and wrongs, to his person and property, his relative rights and character; he may sue and be sued. He owes a temporary local allegiance, and his property is liable to taxation. Aliens are either alien friends or alien enemies. It is only alien friends who have the rights above enumerated; alien enemies are incapable, during the existence of war to sue, and may be ordered out of the country.

Alien Define Alien at Dictionary.com.
They were quiet for a while, and then Marsh turned to Henry and said, Is" that alien to you." At Rumpell's' and at Boveyhayne he had had no sensation of alien origin. His sense of being an alien in Dublin had persisted all the time that he had lived there.

Alien law Wikipedia.
an illegal immigrant, illegal alien or undocumented alien is person who is residing on a non-temporary basis in a country where s/he has no legal right to reside. It is a non-citizen who has entered a country through irregular migration, 2 for example entered illegally, or an alien who entered a country legally but who has fallen out" of status, 3 or a descendant of one.

alien Dictionary Definition: Vocabulary.com.
a person who is expelled from home or country by authority. a Latin American disparaging term for foreigners especially Americans and Englishmen. an imported person brought from a foreign country. an alien who paid a fee to reside in an ancient Greek city.